Choke power supply- part 2

Moffat is a wizard w ears and nickel in the transformer is expensive, get a quote….

i think it is great what Schitt is doing. The book Schitt Happened is excellent, especially the chapter by Mike…

I am a robot all choked up over part quality…

@oldears , you not understanding my responses does not make them inane.

What I said was:

Whether you put the choke on the input or the output the effect is the same. A transformer reflects the impedance from one side to the other based on the turns ratio

I did not say:

It is inconceivable that someone would state that it makes no difference as to whether a choke is used before or after rectification.

While the values are the same, the net effect w.r.t. choke regulation is the same. If you don’t believe me, work out a small signal model or simulate it. I assume you understand reflected impedance? To your point, when people talk about a choke regulated power supply, they usually mean larger inductors, than the typical minimum used for higher frequency harmonics of the AC line and noise. The transformer has enough bandwidth in this case to put a regulation choke on either side.

Your last post did not say anything I did not say already, I just put in more detail:

Output of a bridge rectifier is DC + harmonics of twice the AC frequency. The choke in combination with the capacitor forms a filter eliminating some of those harmonics, but the choke in combination with the load does as well. Hence, the output voltage can droop. So much for your high dollar, low resistance AC power cord.

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The schematics above are 6 types of ways to do choke regulation. The big inductor after the bridge has wicked overshoot but eventually settles. Normally you put an element across the inductor. Note all the voltages are less than the capacitor alone. That is the load dependency issue with choke supplies. The one that overshoots a little and then settles fast with little ripple is a hybrid of inductance before the transformer and after the bridge. Hybrid approaches are best.

Sorry it is hard to read. Not the easiest editor with embedded images.

If you really want to learn more a about choke applications in power supplies find yourself an amp tech that worked on Fender amps from the 40’s and 50’s when Leo was going for cleaner and cleaner tone. Short story to effectively use choke tech I t requires massive high quality transformers which is a cost and supply chain issue. Unless you take the McIntosh approach and produce them in-house.

We use chokes in our designs more expensive well yes a resister can cost $0.99.  I have seen preamps that use a resistor to stabilize power.  But the average person here does not have a clue.